Air-cooled furnace wall



Dec. 6, 1932.

J- S. BENNETT AIR GOOLED FURNACE WALL Z5 Sheets-Sheet Filed Jan. 24, 1928 Dec. 6, 1932. J. s. BENNETT i AIR COOLED FURNAGE WALL 3 Sheets-Sheet 2 Filed Jan. 24, 1928 Dec. 6, 1932. J, s, BENNTT 1,890,364

AIR cooLED FURNAGE WALL Filed Jan. 24, 1928 3 shets-Sneet 5 Patented Dec. 6, h .v

.UNITEDSTTES Applicatie; mea Januaryuzi. `1928;` yserial no. s .49,121".yV

My invention I relateslto furnaces, `andit has for,` one objectfthe provision of means, wherebythe loss of `heat due-'to .radiatlonl from boiler walls may 'be reduced to a negli gible -fvalue andthe efficiency of the furnace thereby increased.' A ,y

Another object 'of my invention 1s to pro-V vide means, whereby the infiltration of .air into the furnace may lbe-very greatly` m1n1. miZed.; Y

A further object'loflmy invention-is to Vpro-V Vvide an aircirculating-s'ystem, whereby the heated. air may be removed" from above the ,boilers ofthe furnace... f i

'A still 'further object lof my'l invention is to shownV that the preheating; effected "by :this

"method is just the proper amount resulting in the removal of the moisture.fromthe coal andexpediting combustion in that portion of the furnace where ignition is about to take place.; Since the preheatingfis nottoo grea'tfy there is no need for'sp'ecial protection -for the exposedfurnaceparts.,` Hence, the airis pre` .heatedl to just the .proper extent without the use. of expensive preheatersi;`

Other objects and :applications of my`in- 'ventiom as well as details of construction and operation, will be apparent more fully hereinafter, .when ,takenl in connection, 'with Vthe accompanying drawings,lwherein Fig. `1 is Vafvertical'sectional` view of afurfV Y nace .embodying myA invention ;4

2 j Fig. 2 a transverse sectional view taken -ontheline 22 of Fig. 1;

FigQSiis a sidel elevational view of. the

. structure :of Fig. 1` from` the outside ofl --the furnace;4

Fig. 4 is an enlarged, detail, horizontal-sectional view taken on the line 4--4.of Fig. 2;

Fig. 5 is a sideelevational'viewof 'the structureof Fig. @and i f fFigs. 6 and 7 Vare'detail'.,sectional viewsof the secondary wall takenfion "the lines 6--6 and 7 7, respectively, of Fig. 5. v f

C AIn-cooLEn FNACE wam.

- opening 11. n

ture:

pocket 8 at. thebase of-:whichisj' Pair Vof The furnace '1' boiler. 4system 113. For purpose of illustra rotary grinders 9. Access, may be had t'the" .y AV,stokerportion of the furnace 4throughan '6.0

yfurther comprises a pairofv Y brick. side wallsf12-'12. fThesevJwalls extend ,Y @vertically 'upwardly.ilandffrin...combinationV with thefwalls 6 and 7,;formiia setting foryja tion, a` s'terling-typeboiler system has been` `shown comprising. a lowerl dlzlmli fand up? 1 per'drums 15, 16 `ancll? whichare respectivev ly interconnected with thejzdrum-Mby groups` of pipes A18, 19 and 2l. The-upper; drums `1,5, `lxand 17 may-be suitably supported'` andare f protectedgby. a covering 227`which extends over the entire upper endijof ltheboiler setting', completely enclosir'rg;thesame..`

'f In the course of the `operation ofthenffur- :nace 1. `considerable heated; air accumulates in. a region 23 which is positioned between the upper c0veri`ng22 ofthe furnace and the ceilingr ,4 of the'boiler room Y 2l l The lgeneral practice,fheret ofore, has'beentoiremove this L f A heat bv providing openvwindowsy A.through which theyheated :air may escape tothe outf side ofthe boiler room 2. ;Thus,j. tli`ere is considerable energy lost. This llos's,v` is' pre1 f jvented inthe practiceof my invention as will] presently"appear. 1 f' A second lossf in 4the boilerl systems. of the l. 'p,riorart isthat due to'heat radiation through -the"wa'lls ofathe" furnace. In accordance with `my invention, this lloss V.also is climinated,andairis suppliedtoja desired portion 24 ofthe fuel bed at just the properftempela-,- f j The yabove-noted desired; resultsfare accomplished 'in' the manner?shown` infthedrawings, wherein a pair'fof secondary .side 'w'alls2525'are spaced fromy outerwsides Y 2,6-26 ,of the-mainside .walls 121-912, so as'to simplify the description, one of ytheseconjd` k...#iooy `.aryfsldeWalls and its associatedalr `passage f fao only is hereinafter descr'bedin detail. rlhis :secondaryvvall 25 may be eXtended upwardly fromthe floor 3.of the boiler room 2 to a vpoint 28 adjacent to van upper end 29 of the Vboiler setting 1,` as, shown particularlyy in Fig. 2. Affron't :portion ofthe air v"chamber I 1,27 is closed'by an end walll 315 While a'rear portionis clos-ed by an end Wall 32. vThe i --bottomV portion f ofathe 'chamber 27l may be"y 1Y0 closedfby, the floor 3'0f the boilerroom, Wh'le the upper portion 33 is entirely, open,V so that y 'desired 'heat-resisting 'material' maybe :posi-y tioned bettveenzthe' `flanged port: on f3.9 of one vertical angleand the flange portion 38 offa 1 second verticaliangle--spaced therefr'o'n'i,- 'rear- ,ward I movement being. l-preventedirby` the flange lfportions y37 and v136* thereof. 'Each of 'A Vthe horizontal members 35v Which-serve to support further Lone of Ythe panel vsections V 40 fin anydesired'i'frertical`V position on thespaced yand ,flange 43 vengagesfanupper edge ,n of a vertical members 34 Vcomprisesv a vpair of- 'a-ngle 's .41,Y iianges '42' and 43 of Whch'are positioned in' abutting relation, so that flange 42lengages a lower edge of one'p'a-nel section 'lower panel section. Q The remainingjflanges 44 .and 45 engage thei rear f y i adJacent panel sections.

Y sides ofthe two vAn' outward movement'of panel 40 away from the anges 36, 37'and 44, 45 may bek preventedby vertical and horizont-al angle sections y46"and 47 respectively.' As -E'shownV in'Figs.' 4 tof7,-f'n-cl usive, the langlesf46fand v' 4'7l are detachably 1 1securedjin" position "by bolts vor in anyjother-d'esi-r'ed manner, vso that the panel/4011x1215? begreadily removed in the adjacent portion ofthe furnacel vvall'. Such vrconstruction',- therefore, .permits a-ny desired portion of the furnace Wall Ato be reached without 'destroying or lremoving:the Whole of the secondary Wall '25. A similar second-i'V aryi Wall may be provided foi-the front and -rear Walls 6j and 17, respectively, butl thishasl not beeny illustrated in'. orderto simplify the `de'scriptiontofithejinvention." Y

l The rearend'ivall 32'of-the yairfrchamber 27 is provided withy an openng '48'Which is positioned yapproximately' midway.. between the Hoor?) and the top of the furnace,v and-it ls'connected'byA aduct 49 to one sde() ofa 'e y suction fan '51.1 -An opposite side of the suction fan 51 Vis'similarly connectedto'the other air' ductl 27e. A discharge vconduitsystem:.'52

Aa,moczleratecost.: l Y i y, further feature"of'myginvention i'sthe 5S- positioned directly belowthe stoker 5,

"leading" from the em 51 Opens into an air box n whereby the Jair passingfrom said ail-box may be forced fuel bed24. y n fWhenthe .fanfl is actuated, heated air is through thestoker into the s Y fm,y 7

Withdrawn'from the portion y2.3 of the boiler 1 l room'2 and caused to pass through thear duets 27e-27 over thefouters'ide 26of ,the fu-r vnace side walls2525, thereby absorbing the, heat radiating therefrom., jThe'already heat-r n iedairisthus furtherpreheated;V and eXperi-Y lence has showirthat the final temperature ofthe "air i as itv passes through thev ducts V49 lis justthe properl value y'to obtain the best results inthe Yfurnace l. 'Since 'the'ipre'heat- Y Y'ingis not `too Vgreat,there* is no-need for y special protection for thestoker andl parts.

finc'ontact with theheated"airv passing ouftfof.,

thevvind box` 53. It is'also noted thatthe'iL vdesired amountof'preheatingvk isobtained Without'the useofaddedequipmentyand:that the simplicity and cheapness lof 4'c'onstruetionif f' of thepreheating. systemrenables --itjtojbe tot applied to f existing furnace Einstallatifons :at

provision of means,wherebyithe air may be caused to traverse ya circuitouslpafth-through l the air'lducts 27, 27 ever the outer fa'ce 26 of '0 the Walls 1245172, thevelocity oftlieailr being .n y

increased over ya portion- 5410i the furnace 1 which extends forwardly and downwardly e between" 'the primar-ys and secondary walls kT112 'and 25'from anupper 'rear edge portioni Y Y istructure 55 terminates lat' apoint?, 4which ofthe air duct 2:7. fAs showninfFig.-

is disposed' nspaced'relation "to the :furnace 'front Wall 1 and to thefuel bed 24, and which vis immediatelyl adjacent vto the hottestportion effect of thev structure 55 on l the heatedlair 'if currents through the-conduits-Q? ,127isshovvn Y *e n l by the dot-anddash linesof Fig. l.

i t eventvthatitfisdesired tofhave accessto the." Assumingfth A vpresen'ceyof :av heated. fuel*y bed 2li-and desperation ofthe am 51, tiri in the regiones between they upper end ff" the furnacefand the :boiler room vceilingff4 becomesvery hoti., The heated air inthe region ,23 is drawn into the air'duts ,Q7-A27 the direction shovvnby'the varrovvs in Figs.

the hottest portion 5K4Jof therfurnlace' .Walls l 124-12,` being increased so. 'astp fpelfynitr fxy 'greater' absorption of the heatfromthg poryvl i' by thefanl and caused'y to pass overtheouter,A Y

Vsides 26- 426 of the furnace,walls12-12in Y 1 and 3,fthe 'velocity voftheT heated/air over N Y v tion` ofthe furnace?Walls'.y When the' airv 48 and'discharged from the ,fanl through `prior art.

portion of the furnace below the stoker 5,

thereby facilitating combustion conditionsV in the fuel bed, particularly that portion 24 where ignition is about to take place. .K Thus, the eiiiciency of the furnace isvery greatlyr increased, since radiation losses throughthe furnace side walls 12-12, as well as from that portion 15, 16 and17 Vofthe boiler system which is in the upperipart' of the furnace7 are substantially elim'inatedfV Moreover, the vengreatly assisted. s i

It is noted that the foregoing sidewall air ducts causes the substantial'eliminationof-a third furnace loss, namely, that diie v'to the in-v filtration or leakage of air into the furnace through the' brick work ofthe walls,` ,This loss sometimes isa very serious one, sin cethe additional air entering thefcombustion chain-V ber is sufficiently great to causea largefde-V crease in the ei'liciency of combustion." The positioning of the air ducts V27, 27 on tli'eoutside of the furnace walls, `provides a seal, wherein a negative pressure-is maintained* by the suction effect of the fan whichis equal to or greater than the negative pressurein the furnace.

lVhile I have shown only one form of femi bodiment of my invention, for'the purpose of describing the same and Aillustrating its is apparent that various changes and modifications may be inade'therein without der parting from the spirit of my inyention. For example, the fan 51 may be positioned above `the furnace and caused to force, rather than draw, air through the ducts 2T. Ijdesire, therefore, that only such limitations shall be imposed thereon" as are demandedv bythe I claim f 1. A furnace comprisingvza Stoker, a side wall extendingV upwardly from said stoker, a boiler system having one part thereof vpositioned in the upper portionlof the furnace, v

a wall spaced from the exposed side` of said side wall to form an air passage, one portion of said side wall being heated to a Vgreater extent than the other portions thereof, means whereby air may be drawn throughsaid air passageover saidexposed side of the furnace wall, andA means positioned in said passage may be increased.

2. A furnace installation comprising a y side walls, respectively, to forin airfducftjs,

means whereby the heated air atv the upper portion 'of' said furnace may be drawn through said air ducts-and thereafter sup-,

`adjacent'the topof the furnace* to afford thereat an opening to the spacev between said.-` walls `substantially co'entensive` with #the f plied to saidfurnacaand meanswherebyfthe *velocity of the airpassing through said'ducts4 t t maylbeincreased oyersaid first-mentioned Jportionsofsaid sidewalls.' y. fAfurnace coinprising'a supportfor afg'if)f fuel bed, a boiler system associated', ltheref A`with,"aivalls surrounding said?` fuel"v support` andthe boiler system andj constitutingthe n i inaiiiwalls of the furnace, Aa `supplemental wall spacediapart from said main wallandgf terminating' adjacent the top Vof the furnace tilation ofthe power plant as a whole is very tween sa'idf walls substantially coextensive with the! width of said supplernentaliwalhV if' said supplemental wall `being- Vccfiinposed` of0ll to afford thereat an openingto the space-bedetachable, panels affording accessi toathe main walla blower lconnected with. the 'low.

heated air drawn from above the furnacefbe- 4, A fuel bed, a boiler system associated therewith,`

walls surrounding saidlfuel supportand thef,d boiler system and constituting the niainiwalls e of the'furnace, `a-supplenientalwall spaced apart from said main Vwall-and terniina-ting width of said supplemental wall, said supplemental wall being composed of detachable panels affording access to the vmain wall, a blower connected withthe lower portion of; the'space betweensaid main and supplernen#4 whereby air above :the furnace is drawn t downwardly into said space, a duct connect#l support, whereby theheated air drawn from above the furnace between the main and supl plemental walls is supplied :to thefurnace for combustion purposes, and bafi'le elements be# tween they rnain andvsupplernental walls are velocity of the airovergivenportions ofthe surfaces of themain walls. .i whereby the velocity of the air passing' over said rst-mentioned portion of said side wall 5. furnace installation comprisingv main walls'constitutin'g a mount vfora boiler sysapartfrom saidV :main walls and terminating adjacent the top of the furnace, a blower connected with the lower=portion-oftlie spacel between said walls and adapted to levacuate said space whereby heated air above tlieiuri nace is drawn downwardly into said space, a duct connecting the blower withthe space im`4 4er portion ofthe spacefbetween said main v and supplemental walls-and adapted toievace` nate said space whereby airy above-the furx nace visdrawn downwardly into said's'pa'ce,A i y and a duct connecting'said blower withthe n 1- t sp'acejbelow the/fuel support wherebythe'fV .fg-

tween the-,main and-'supplemental wallsfisro4 suppliedto thefurnace for combustion jpurg Y poses. .Y i J furnace comprising ,a-jsupportfor l io'5 Y,

I talV walls and adapted to evacuatesaid space-f` i1`0 ing said blower with thespace below the fueh;

i115 ranged to afford restrictions increasing the 12o a `teni, a support for a fuel bed established with t t Y in said walls, va Vsupplemental wall spaced f .mediately vbelow the fuel b d support, andal "1. i

Y Y i. v 51,890,364 Y 'baille means between. the said. Walls forming a: restriction inthe air'channel tata, point vimmediately; adjacent Athe-sp"a ce above said f c fuel' bed support whereby air drawn between '5p the Walls is accelerated in'its movement past the hotter portions off-the main Walls.V

6. A-A'furnaceinstallation .comprising Aa Stoker,l a boiler positioned above said Stoker, `vWalls enclosing said boiler andstoker, 'said g' 7510 Walls comprising. a refractory-portion Vand a relatively thin portion spaced outwardly v therefrom tovforni an airduct extendingcon` tinuously and uninterruptedly from the-topf 1 of tlieboiler to thev bottoni of'said installa- -i`f15`tion, they last named Wallportion'v being z formedV of a series of detachable panels af? fordingaccess to the inner `Wall portion, and .means for drawing air into said duct at the' top fronrthe space above the boiler and feedi'fzofing it. into-the furnace beneath the Stoker,

jf'through-into the furnace;v s

' 7. A (furnace installation comprising a 1 --stoke1`, a boiler and Va hollow Wall --housing 25V said Stoker andboiler, said Wall comprising a er relatively thick refractory inner portion and a relatively thin paneledk outer portion in l spaced relationthereto, the space between f, Y Said Wall portionsconstituting an air Aduct gorfextendingvcontinuously from the :top to the bottorn'of said installationfand,means forf i drawing air into .said duct from the space,V above the said Ainstallation and lfor subsel quently foreingthe heated air'nto the fur- Y35' nacebeneath'the Stoker. Y

' JOSEPH S. BENNETT;

- saidfwalls preventing infiltration of air thereil i 

